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HomeMy WebLinkAbout1 Holleman Jones Butler Roundabout4-·~n'1S ·~CJ 11/22,21 , 1:35 PM Pedestrian Fri end ly Roundabouts I Insights I Crafton Tull CRAFTONTULL INSIGHTS Ins ights (/insights) Engineering (/insights/categories/view/16/engineeri ng) Pedestrian Friendly ROl,md abouts (/insights/posts/view /63/pedestria n-friend ly-rou nda bouts) PEDESTRIAN FRIENDLY ROUNDA BO UTS Engineering (/staff/view/26) Bill Burnett (/staff/view/26) P.E . Vice President Roundabouts have steadily emerged across our nation in recent years and have even become the new norm for many of our communities . The numerous benefits of roundabouts , including continuous traffic flow and decreased severity in crashes , are undeniable . However, there are a lso some poorly designed examples that showcase why it is crucial to design and construct roundabouts in an exceedingly prudent manner. This holds true , not only for veh icular considerations , but also for pedestrian safety. There are some misconceptions that roundabouts pose a greater danger to pedestrians than traditional intersections with traffic sig nal or stop sign control. Roundabouts are a proven way to increase safety and effic iency for all those sharing the road - including pedestrians. Federal Highway Administration and Insurance Insti t ute for Highway Safety studies have shown that properly designed roundabouts result in as much as a 40 percent reduction in pedestrian collisions along with other significant improvements in safety over more traditional intersections . Pr ivacy -T~rms httne ·//unrn., rr:>ftnnt11 11 "nm /in<=:inht <=:/i nsiaht oosts /v iew/63/pedestri an-fri e ndl y-ro undabouts 1/5 11/22/21 , 1 :35 PM Pedestria n Friendly Roundabouts I Insights I Crafton Tull A proper roundabout design is critical and must consider vehicles and pedestrians equally for a well-balanced solution that provides ample capacity, reduced delay, and increased safety for everyone . Unfortunately, pedestrian considerations are sometimes given a lower priority and are often treated as more of an afterthought rather tha n an integral component of the design . Below are some guidelines for designing and bu ilding a pedestrian friendly roundabout: 1. Speed Reduction Design the roundabout approach curves to progressively reduce vehicu lar speeds prior to entry. Slower speeds at or below 20 mph are much sa fer and enable pedestrians to find gaps in traffic to safely cross and encourage vehicles to yield to them as they step up to the crosswalk . 2. Central Island Place earth fill and architectural features in the central island to make it visible to approaching drivers . A raised central island prevents drivers from seeing all the way through to the other side of the roundabout and encourages them to slow down to negotiate the turns . This places the driver 's focus and attention back to the near side crosswalk rather than looking further ahead through the roundabout. 3. Splitter Islands Provide refuge for pedestrians within the splitter islands of sufficient width to accomm0date the length of bicycles . The refuge island allows pedestrian and bicycle users to look left first at oncoming traffic , then look right after reaching the island. Negotiating traffic one direction at a time reduces the user stress levels , which can lead to a safer outcome. Raised splitter islands with low landscaping or architectural features can encourage reduced vehicle speeds and make pedestrians feel safer while in the island as long as the low elements don 't block visibility. Privacy· Terms https ://www.craftontull.com/insights/insight_posts/view/63/ped estrian -frie ndl y-roun dabouts 215 11/22/21 , 1 :35 PM Pedestrian Friendly Roundabouts I Insights I Crafton Tull ~ 4. Lighting RAISED CENTRAL IS LANO Install roadway luminaires in the appropriate locations on the approach side of each crosswalk . This ensures that pedestrians are illuminated from the approaching driver's point of view. Lights installed on the opposite side of the crosswalk will illuminate the wrong side of pedestrians , causing them appear as shadows from the approaching driver's view. 5. Crosswalks Follow FHWA guidelines on placement of crosswalks to allow for one car length or approximately 25 feet from the edge of the circulatory roadway. Vehicle speeds are re latively slow in these locations . Consider raised "speed table " type crosswalks that offer more visibility along with slower speeds that can encourage vehicles to yield to the pedestrians . Speed tables also reduce the need for ADA curb cuts allowing wheelchairs and bicycles to continue through the crossing at sidewalk level. 6. Pedestrian Channelization Consider adding pedestrian channelization features such as railings , bollard-and-chain barriers , landscaping , planters, or other architectural elements . Such features will guide pedestrians to the appropriate crosswalk locations where scattered or random crossing movements become problematic . 7. Striping & Signage Place crosswalk striping and accompanying signs in such a manner as to maximize their visibility to drivers . Consider high- contrast colored and patterned pavement treatments to provide additional visib ility for the crosswalks . Advanced warning signs should also be placed to alert drivers they are approaching a roundabout and encourage speed reduction . Striping and signage are absolutely critical to the function of roundabouts and should be refreshed on a regular basis. 8. Additional Pedestrian Warning Treatments Consider additional signage and signals in areas of heavier pedestrian movements . Such treatments could range from simple flashing beacons , to pedestrian activated devices such as LED edge lit signs, Rectangular Rapid Flash Beacons, or embedded pavement lights, to full-fledged pedestrian hybrid beacons or "HAWK" signals . If possible , extreme ly heavv pedestrian volumes should be re-routed away from a roundabout via a tunnel or bridge . 9. Public involvement an1 awareness Privacy · Terms ·--A --•· .II -~-1;~~;~hlc/;nc;nhl nn<;l!'</ViP.W /63/oedestrian-friendly-roundabouts 3/5 11 /ZZ/<'1 , 1:;j5 PM Pedestrian Friendly Roundabouts I Insights I Crafton Tull It is no secret to those in the industry that roundabouts can be a hot-button issue . One way to allay community concerns is to keep residents in the loop through public outreach via the city's website, social media , and press releases. The FHWA compiled a Roundabouts Outreach & Education Toolbox (https://safety.fhwa .dot.gov/intersection/innovative/roundabouts/roundabouttoolbox/) to help cities and towns ga in support for roundabouts, including animated videos . Cities across the U .S . are seeing the benefits of implementing roundabouts into their transportation networks . As mun icipal engineers manage the design and construction of these types of transportation nodes , ample consideration should also be given to pedestrian safety using the guidelines above. 335 Share Tweet Sha re Email Share Shares QUICK LINKS o Contact (/pages/cont act-us) o Careers (/pages/careers ) o Who We Are (/pages /who-we-are) o What We Do (/pages /what-we-do) o Proje cts (/p roj ects) o Our Pe ople (/s taff) o News & Media (/news) o Ins ights (http ://www .c raftontull.com /insights) ABOUT US Crafton Tull began contributing to the built env ironment in 1963 and has not stopped since . We are a 100 percent employee-owned civil engineering , surveying, architecture , lands cape architecture , and planning firm with more than 200 employees and multiple office locatio ns throughout Arkansas and Oklahoma . Our longevity, cou pled with continuing investments in education and technology, has led to co ns is tent growth that we plan to continue into the 21st ce ntury. With a focus on outstand ing client serv ice , our profess ionals deliver quality professional design and surveying to our clients across the country. Read More (/pages/who-we-are) CONTACT US Enter Name Enter Company Enter Email Address Enter Phone Number Pr ivacy ·Terms https://www.craftontull.com/insights/insight_posts/view /63/pedestrian-friend ly -ro undabouts 4/5 11/22/21 , 1:35 PM Enter Message What does 8 + 5 equa l? SUBMIT © 2021 Crafton Tull. All Rights Reserved . Pedestrian Friend ly Roundabouts I Ins ights I Crafton Tull ROGERS 4 79-636-4838 TULSA 918 -584-0347 OKC 405-787-6270 RUSSELLVILLE 4 79 -968-1885 CONWAY 501-328-3316 UTILE ROCK 501-664-3245 FAYETTEVILLE 479-455-2207 .... __ .,,, ...... rr<>flnnli di rnm/in~inht~/insiaht oosts /view /63/pedestrian-friendly-roundabouts f in (https :~~.t fref=ttijttpstfJ~i)bWlors Pr ivacy -Terms 515 < BACK OF CURB ~ ..... -llL.. ....... ~ ...... ~~+1--.!.!:'.'....__ HOLLEMAN DRIVE Kimley»>Ho rn MEMORANDUM To : Ed McDonald , P.E . From : Dana Shumard, P.E. Kimley-Horn and Associates , Inc . Date: February 3, 2022 Subject: Response to Holleman West Conceptual Comments This memo is to summarize responses to comments made by the City received by Kimley-Horn on November 22 , 2021 . Planning and Development 11/22/2021 1. Could the crosswalks possibly be designed as speed tables? Response: Both streets are on the Emergency Response Routes so installing speed tables is not a preferred option. 2. Based on the crosswalk location would RFB 's be recommended or needed in the future? If so, how would this need impact design? Response: Solar RFBs can be included in future design and pedestrian volumes warrant. Since the RFBs will be solar, these can be easily added in the future. 3. Does the traffic model take into consideration the change on traffic patterns that will come with Jones Butler being extended across FM 2818? Response: Yes. 4. Can the curb radii be reduced to slow vehicles down further prior to interacting with peds/bikes at the crosswalks? Response: Yes, we have reduced the lane widths and curb radii to further slow speeds. 5. Would it be recommended to move the crosswalks further from the intersection? Response: For speed control and pedestrian safety, we recommend moving the crosswalk closer to the intersection. NCH RP 672 recommends placing crosswalks 20' from the intersection for mini-roundabouts, -one car length. This allows for one car to stack and moves the pedestrian crossing closer to the intersection where speeds are slower and where drivers are conditioned to seeing pedestrians cross at entries and exits of roundabouts. We considered placing the crosswalks further back -45' to allow for a bus to stack ahead of the crosswalk but recommend not doing this due to visibility concerns. kimley-horn .com 2800 South Texas Avenue . Suite 201, Bryan. TX 77802 979 775 9595 Kimley»> Horn Page 2 Buses may shield pedestrians that are crossing behind the bus to the splitter island from the view of drivers exiting the roundabout For this updated concept we have placed the crosswalk at -20' 6. Can the entry and exit lane widths be reduced to minimize any additional right-of-way? Response: Yes, we have updated the entry and exit widths to reduce the impacts while still providing enough width for the design vehicle on-pavement and the accommodation vehicle within the perimeter curbs. kim ley-horn .com 2800 South Texas Avenue . Suite 201 , Bryan , TX 77802 979 775 9595 ~l/22/2l 1:19 PM The Roundabout Way to Safer Intersections I by A lta I Oct, 2021 I Alta The Roundabout Way to Safer Intersections ~A1ta ~Q \;.J' Oct 22 · 6 n 'n read By: Kristie Di Cocco ,..EE, Senior Engineering Associate, Alta At their worst, roundabouts fail to safely address the presence of bicyclists . At their best, they are a great way to calm traffic and reduce greenhouse gas emissions while providing dedicc.ted space and safe crossings for people walking and biking . Roundabouts are a critical tool in the traffic management toolbox as they provide both efficiency and improved safety, but they aren't the right fit for all locations. Engineers see the biggest benefit of roundabouts in their ability to maintain vehicle flow while reducing vehicle del ay. From a safety perspective , roundabouts reduce pedestrian crashes by-21._percent and vehicle crashes by_.1.B_percent when compared with signalized intersectio n s. In fact , crashes aren 't just reduced in number bu t also in severity, as roundabouts have a l.8_percent reduction in injury: crashes over signals. At Alta, we are working towards a future where roundabouts not only enjoy the above benefits, but also provide for the safe and efficient moveme nt by people riding bicycles and other mobility devices . Through innovative solutions that mimic protected intersection trea ments, people walking and biking can be separated from the main circulatory flow of traffic . This dedicated space provides comfort, but also improves visibility. Round a bouts can also serve as gateway opportunities to visually notify people h ttps ://blog . a Ila plann ing .com/the-roundabout-way-to-safer-intersection s-1 a3 3 7 Od 9 33 bf {S) Show less li ke this Mute th is au th or Mute th is publication Report 1/5 11/22/21 , 1 :19 PM The Roundabou t Way to Safer Intersections I by Alta I Oct , 2021 I Alta driving that the character of the roadway is changing and they are now entering a different driving environment . For example, Alta is providing active transportation design in Anacortes, Washington with the most vulnerable road users in mind . In doing so , we are able to provide a true mult i-modal solution that addresses climate change, promotes walking and bicycling and addresses traffic issues all in one round solution. There are many examples of successful roundabout projects in communities across North America. Here are some Alta is excited to share. Anacortes, WA Commercial Avenue Complete Street Left: Signalized altern ative with dedicated space for other modes of travel. Right: Wider crosswa lks and crossbikes coupled with Rectangular Rapid-Flashing Beacons (RR FB 's) provide increased safety for nonmotorized users . As part of the Commercial Avenue Complete Street Plan that Alta helped the city develop in 2016, we are working with Transportation Solutions, Inc . to design a roundabout for the City of Anacortes , WA. The 2016 vision established a new multimodal framework for the Commercial Avenue corridor that transfe,rms the WSDOT roadway into a space that is also comfortable and safe for people to walk and b ike . The first phase of design is focused at the most prominent intersection along the corridor that is both a gateway into the downtown core and a junction to the Anacortes Ferry Terminal, a popular destination point. The project plans to reconfigure the intersection from a signalized intersection into a roundabout. Through this process there have been a number of important technical discussions around a design within a constrained space that is able to accommodate higher traffic volumes while also The project team is in the early stages of evaluating the inclusion of fully separated facilities w ithin the single lane roundabout through a dedicated 6-foo e,ne-way cycletr ack for bicyclists and 10-foot sidewalk fo peclestrians. This is in contrast to many traditional design approaches that will either force bicyclists into the lane, onto the sidewalk while walking, or include a bi-directional shared use path. Rectangular Rapid- Flashing Beacons will enhance crossings at each leg of the roundabou and bo th crosswalks and cross bike s are incLuaed at each crossing to continue se paration https ://blog .altaplann in g .com/the-ro un dabout-way-to-safer-in tersections-1 a3370d933bf 215 >11122121, 1:19 PM The Roundabout Wa y to Safer Intersections I by Alta I O ct, 202 1 I Alta This high-profile project has the opportunity to help create a paradigm shift for state highways in Washington State and serve as an example for other communities on how to transform t h eir own state highways into multimodal corridors . Palo Alto, CA Bike Boulevards ~ -...-"~ ~ Alta worked with the City of Palo Alto, CA to plan and design safety improvements along nine bicycle boulevard corridors throughout the city. After the initial phase was completed, the City selected Alta to prepare design construction documents for four of the corridors. These projects include urban roundabouts, among other traffic ca lming elements aimed at enhancing the bicycling experience along the project corridors. The final design of these four corridors included 11 compact roundabouts, which are similar in size to mini-roundabouts, but include more traditional roundabout elements such as landscaped center islands . Due to the restricted size, some larger vehicle turning movements were prohibited. A critical aspect of the corridor design was to maintain the comfort of bicycling along the corrid ors and through each intersection. To achieve this , Alta paired the roundabouts with other traffic calming elements such as speed humps, chicanes, and raised intersectjons . The effective use of the compact roundabouts as intersection treatments coupled with the traffic calming corridor elements reduced vehicle speeds and offered bicyclists the opportunity to maintain their physical presence on these low-stress streets leading up to and after the roun d abouts. San Diego, CA Pershing Bikeway https ://blog .al ta plann ing.com/the-round a bout-way-to-safer-intersections-1 a3370d933bf 11/22/2 1, 1:19 PM T he Round a bo ut Wa y to Safer Intersections I by Alta I Oct , 2021 I Alta Before/After of t he Pershing Bikeway (re nd er in g). IUS..U.1111f0,!llCNAOl'.V.~ll~NCJ'"[t !UMl'tSWl 1SC ~·s ·101uuw•1"..H11 1 KfCMI "'..t.Jd rCllll'lllaPOSl':!:llUIDN;IM>DC-Ol'IAU; ) TKCO .. 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UM.1.'llUll'~>mt .:Otcl _ .. 8 '"'14'Wll;l~J~•·"'''""'llf lt ~ ""'1 .... 1-"llUlt"C'ICL!IM<ol-VSllf\T•ln•IKl~\7.WTIU lltU G!) lilt>t .... l •l A'C.1'~1..:U..imo.c. '6'Mol'l.ID'1ld \.11111~ El ·~ ...... -... --·~·· .... • .. -~··· ~,..,"" __ ,,.._.,..._"' __ ~co••-"" G -·~•<KU•-•••-••-~--~•m•~~· - ~-1 ..... "",_,.,. .. ,,11(.o ......... . [?] =~"1 Mfl>IO .. """'°"•-~u.u rl1'0 .. •Mm!ll -1'11DPl..,.IJ'9•r::'.=-:-::'.=---,--::: -,\;-£;.;:• San Diego is nearing completion of one of its most visionary projects, and Alta has been there every step of the way since 2015 . The project is in the process of biddin g for a 2.6- mile separated bikeway along Pershing Drive through historic Balboa Park. Th is project is part of the $200 million Regional Bikeway Early Action Program for the San Diego Association of Governments . The bikeway design will prov id e a crucial commu ter connection between the North Park neighborhood and downtown San Liego. Alta led community engagement, concept alternative development, preferred concept adoption, visual renderings, the engineering plan set, preliminary environmental review a n d agency coordination. The project includes an urban compact roundabout with a n a djacent neighborhood traffic circle, as shown in the plan image above . Caltrans defines a compact urban https://blog.altaplann ing .com /th e-ro undabout-w ay -to-safer-i nterse ctions -1 a3370d 93 3bf l ~ ""' ~ IZl ~ S&-12 4/5 11/22/!1 , 1:19 PM N • S App Store The Round a bo ut Way to Safer Intersection s I by A lta I Oct , 2021 I A lta roundabout as a single lane roundabout in an urban setting with an inscribed circle diameter of 115 feet or less, and exit radii of 39 feet or less. This compact design allows for the safety and flow benefits of a traditional roundabout to be experienced with reduced vehicular travel speeds and a smaller spatial impact on the surrounding landscape. The project also features a large single lane modern roundabout with several key challenges. The project is located on the side of a hill with challenging grades; it also features three le15s that create geometry that make it more difficult to control entry and exit speeds. Alta's design evolved to modify the approach of Pershing Drive to act more like a right angled (square) intersection. Along with the roundabout, Rec t an gular Ra p id Flas h in g Bea cons (RRFB s) will be implemen ted a t eac h leg of the ro und a bout, w hich will i ncrease t h e vi si bili ty of ped estri ans and bicyclists cross in g th e ve h ic ul a r trave lway. All in all, the design will take an intersection that has traditionally been difficult to navigate and transform it into a space that will be safer for all roadway users. After so many years of hard work by so many champions, we are excited to see this project under construction! How have you seen multi-modal roundabouts in your community? Where would you like to see more? Learn more about Alta's Engineering practice, and contact Kristie Di ~if you'd like to see more roundabouts in your community. Roundabout Engineering Traffic Engineering Cyc ling Transportation ~ G~o~le Play https ://blog .altaplann ing .com /the-roundabout-way-to -safer-intersections -1 a3370d93 3bf 515 ·-NACTO I National Aaoclatlon of City Tra-rtatlon ottlclail NACTO Executive Board Janette Sadik-Khan Principal, Bloomberg Associates NACTOChair Seleta Reynolds General Manage r, Los Angeles Department of Transportation NACTO President Robin Hutcheson Director of Pub lic Works, City of Minneapolis NACTO Vice President Robert Spillar Director ofTransportation, City of Austin NACTO Treasurer Michael Carroll Deputy Managing Director, Office of Transportation and Infrastructure Systems, City of Philadelphia NACTO Secretary Joseph E. Barr Director, Traffic, Parking & Trans portation, City of Cambridge NACTO Affiliate Member Representative I Working Group Cara Seiderman Community Development Department, Cambridge, MA Ted Wright New York City Department of Transportation Carl Sundstrom, P.E. New York City Department of Transportation Peter Koonce, P.E. Portland Bureau of Transportation, Portland, OR Mike Sallaberry, P.E. San Francisco Municipal Transportation Agency Peter Bennett San Jose Department of Transportation, CA Dylan Passmore, P.Eng. City of Vancouver, BC David Rawsthorne, P.Eng. City of Vancouver, BC Dongho Chang, P.E. Seattle Department of Transportation Advisory Committee NACTO Cities for Cycling Committee representatives NACTO Project Team Corinne Kisner Executive Director Kate Fillin-Yeh Director of Strategy Nicole Payne Program Manager, Cities for Cycling Matthew Roe Technica l Lead Aa ron Villere Senior Program Associate Celine Schmidt Design Associate Maj ed Abdulsamad Program Associate Technical Review Joe Gilpin Alta Planning & Design Vignesh Swaminathan, P.E. Crossroad Lab Acknowledgments This document was funded by a grant from the The John S. and James L. Knight Foundation. Special thanks to Robert Boler from Austin, TX for providing the inspiration for the title of this document. Cover Photos Top : Vancouver, BC . Madi Carlson Bottom: Cambridge , MA. Better Bike Share Partnership Table of Contents Introduction Intersections at a Glance Reducing Turn Conflicts Protected Intersections Descr i ption Implementation Guidance Determining Clear Sight Distance Using Bikeway Setback to Increase Visibility Setting Turn Speeds through Curb Radii Des ign , Contro l, & Managed Vehicles Variat ions Dedicated Intersections Descr i ption Implementation Gu idance Reduc i ng Turn Speeds and Mitigating Conflicts Variat ions Minor Street Crossings Descr i ption Implementation Guidance 5 9 21 27 Signal Phasing Strategy 31 Leading Bike Interval (LBI) & Lagging Left Turn Bike Scramble Protected -Permissive Bike Signal Protected Bike Signal Build Toolkit 36 Citations 38 I Introduction Better bike networks need safer intersections Since the publication of the NACTO Urban Bikeway Design Guide in 2011, cities across North America have expanded their protected bike lane mileage by more than 600%,1 opening the door for a dramatic increase in the number of peop le biking. However, amidst this growth, design strategies for intersections remain a crucial, underdeveloped part of the bikeway des ign toolbox. Intersections are the place where the most vehicle -bike conflicts occur. In 2017, 43% of urban bicyclist fatalities occurred at intersections.2 On many streets, large turn radii and wide lanes encourage drivers to make sweeping, fast turns. These design decis ions increase exposure and risk for people walking and biking, reduce the safety and comfort of the bike network, and discourage cycling.3 As cities work to make streets safer and more welcoming for bicyclists of all ages and abilities, intersection design is key. Don't Give Up at the Intersection expands the NACTO Urban Bikeway Design Guide , adding detailed guidance on intersection design treatments that reduce vehicle-bike and vehicle-pedestrian conflicts . This guidance covers protected bike intersections, dedicated bike intersections, and minor street crossings, as well as signalization strategies to reduce conflicts and increase comfort and safety. Used in concert with NACTO's Urban Bikeway Design Guide and Designing for All Ages and Abilities , this guidance provides the tools cities need to build comprehensive , connected, safe bike networks. I Introduction Intersections at a Glance This gui de is organize d a round three intersection design strategies and the spec if ic too ls that are most applica ble to each. In combi nati on , these t ools reduce turning speeds, increase the visibility of people bicycling , a nd give priority at intersections to people bicycling. Strategies I Protected Intersections (page 9) Tools Bike way Set back Recesse d Stop Line Bike -Frien d ly Signa l Phasi ng Tu rn Wedge Vertical Se paration Elements Raised Bike Crossing Introduction Reducing Turn Conflicts Turning vehicles presen t a specific and outsized risk to people on bikes. Cities can design safer intersections by reducing turn speeds, making bikes visible, and giving bikes clearer priority over tu rning vehicles . Reduce turn speed. Drivers yield more frequently to people walking and biking when speeds are low, making it safer for bikes to pass in front ofturn i ng cars. Lower speeds give drivers more time to stop if nee ded , and reduce the sever ity of collis ions when they occur. Smaller turn radii, centerline harden i ng , turn speed bumps, and raised bike crossings can all reduce the speed at which drivers turn .• Make bikes visible. Setting back the bikeway crossing, installing recessed (early) stop lines for motor veh icles, and building raised bikeway crossings all make it easier for drivers to see people using the bikeway. The designer 's challenge is to provide good lines of sight without encouraging higher speeds. Give bikes the right of way. People on bikes crossing a busy intersection need clear priority over turni ng motor vehicles. Formal right of way often is not enough, but driver yielding can be improved by prohibiting motor vehicle turns on red, implementing b ike-friendly signal strategies, and letting bikes move past stopped veh icles while waiting for a signal.5 I Protected Intersections Protected intersections have been implemented across North America as cities have expanded their protected bikeway networks. Also known as setback or offset intersections, th is design keeps bicycles physically separate from motor vehicles up until the intersection, providing a high degree of comfort and safety for people of all ages and abilities.6 •7 This design can reduce the likelihood of high- speed vehicle turns, improve sightlines, and dramatically reduce the distance and time during which people on bikes are exposed to conflicts. For example, in San Francisco, a protected intersection design resulted in 98% of drivers yielding to people on bikes, and 100% yielding to people walking.8 A study in New York found that protected intersections had fewer vehicle-bike conflicts than even a dedicated turn lane with a dedicated bike signal phase.9 Description At protected intersect ions , the bike way is set back from the parallel m otor vehicl e traffic. Unlike at conventional bike intersections, people biking are not forced to merge into mi xed traffic. In stead, they are given a dedicated path through the intersection, and have the right of way over turning motor veh icles . The setback betwee n the motor vehicle lane and the bikeway makes peo ple on bikes more easi ly v isible t o turni ng d ri ve rs tha n in a con ventional intersection. Corner islands anch or the design, extending the protected bike la ne's se paration as fa r into the intersection as possi ble and tighten in g the corne r 's turn ra d ius. They create a bike queue area after the crosswalk, t he natural p l ace for people on bikes to wait. The set back creates a waiting zone for turning cars, where drivers can yie ld to bikes after starting to t u rn b ut before crossing the path of oncoming bicycles. If it is large enough, this area lets drivers wa it while th rou gh-traffic passes t hem, reliev i ng pressure to turn too quickly. Protected i ntersectio ns also provi de shorter, safer crossings fo r pe op le walking. With l ow -sp eed vehicle t u rns and ro om for accessib le pedestrian islands, peo ple on foot and using personal mob i lity devices get m any of t he be nefits of curb extensions. Protected intersect ion s create s horter, simp ler crossings, more predictab le moveme nts, and be tte r v isibility between people on bikes and people d r ivin g.As a resu lt, the intersection is more comfortable and sa fe r for peo ple us i ng the bikeway and the crosswalk .10 I Protected Intersections No Stopping I No Standing Zone Motor vehicle parking and stopping are prohibited on the approach to the intersection. Pedestrian Islands Islands reduce crossing distances and improve visibility by keeping the intersection clear. Wider islands support high volumes of people walking and biking, raising the capacity of the intersection. In some cases , islands can reduce the signal time needed for pedestrians. Clear Sight Distance No Stopping I No Standing Bike Yield Line (optional) _J Bikeway Setback The setback determines how much room will be available for drivers to wait and yield, and the angle at which they cross the bikeway. Larger setbacks provide better visibility and give people bicycling more time to notice and react to turning vehicles . --- Bike Queue Area _ __,.___, People biking can wait I ahead of the crosswalk for a green signal or a gap in traffic. This shortens crossing distances, and accommodates the natura l positioning of people biking. Bike detection optional Crossbikes I Intersection Crossing Markings Markings prov ide consp icuity and directional guidance to bikes in t he intersection. They are marked with dotted bicycle lane line extensions and may be supplemented with green color or bike symbols between these lines.11 Motorist Waiting Zone The space be tween the motor vehicle lane and the crossbike provides a place for motor vehicle drivers to wait before turning across the bike's path of travel. Corner Island A corner island separates bikes from motor vehicles , prevents motor vehicles from encroaching on the bikeway, and creates a protected queuing area for people on bikes wait ing to turn. Protected Intersections Implementation Guidance Bikeway Setback: The bikeway setback distance determines most other dimensions of the protected intersection. A 1 O' setback, created in the shadow of the parking/loading lane, is shown. Where practical, a setback of 14-2 0' is preferred . If setbacks smaller than 12' are used, they should be accompanied by longer clear distances , and additional signal phasing or speed reduction strategies should be considered. Setbacks larger than 20' may increase turn speeds, and setbacks larger than 25' should be treated as a separate intersection . Corner Island: Radii should be small enough that passenger cars are discouraged from turning faster than 10 mph .12 This is accomplished with an effective turn radius of less than 18', usually result in g from a 1 O' to 15' curb radius . Corner isla nds may have a mountable override area to accommodate large vehicles. Corner islands may also be i mplemented as channelization markings that are reinforced by mountable vertical elements such as modular speed bumps. Pedestrian Islands: Wider islands support high volumes of people walking and biking, raising the person -capacity of the i ntersection . To serve as an accessible wa iting area, the minimum width of a pedestrian isla nd is 6'.13 The desired minimum width is 8'. If 6' or wider, detectable warning surfaces must be placed at bo th sides of the island to distinguish the bikeway from the sidewalk, and the island from the bikeway. No Stopping/No Standing Zones: Zones should be long enough to allow approaching drivers and bike riders to see and recognize one another ahead of the intersection . Many cities already designate 20'-30' of curb before an intersection as a no -standing zone to increase visibility. Features that perm it visibility, such as plants, seating, bike park ing, and shared micromobility stations , can be placed here.14 Bike Queue Areas: Queue areas should be large enough for anticipated bicycle vo lumes, which often increase substantially after implementation of protected bike lanes . The bike queue area should be at least 6.5' deep, but d imensi ons of 1 O' or greater are desirable to accommodate trailers, cargo bicycles, and high bike volumes.15 Protected Intersections: Applications Protected intersections can be applied on any street where enhanced bike comfort is desirable. They are most commonly found on streets with parking-protected bike lanes or buffered bike lanes. Variants can be applied where there is no bike facility on the intersecting street, as well as streets with two-way protected bike lanes. Protected intersections can also be implemented using interim materials. Where no parking lane exists, a setback can be created by shifting the bikeway or motor vehicle lanes away from one another as they approach the intersection. Accessible Signals: See MUTCD Chapter 4E, PROWAG , other national guidance, and local standards for signal timing and location guidance. Bike Yield Line & Bike Lane Crosswalk: Bike traffic should be expected to move forward to the stop bar on any signal phase, and pedestrian traffic should also be expected to cross to the island on any phase. This operation may be formalized with optional yield teeth on the bikeway before the crosswalk.16 The 2009 US MUTCD calls for a "Yie ld Here to Pedestrian" sign if yield teeth are used . In some jurisdictions, a yield line is not necessary before a crosswalk . Signs: A modified "Turning Vehicles Yield to Bikes and Pedestrians" sign (R10 -15)17 is recommended where a signalized intersection allows right turns concurrent with bicycle and pedestrian movements. It is required in jurisdictions where state/provincial or local laws are such that ped estrians and bikes do not automatically have the right of way over turning vehicles. The sign should be mounted close to any signal head that regulates vehicles turning across the bikeway and any required location . (This modified sign remains experimental under the 2009 MUTCD.) I Protected Intersections Determining Clear Sight Distance At the approach to a protected intersection, a clear sight distance must be provided so that people driving and biking can see one another before the intersection. The clear sight distance is calculated by adding the No Stopping/No Standing Zone, the crosswalk and crossbike widths, and the bikeway setback. The length of the clear sight distance is determined by the speed at wh ich both cyclists and motor vehicles are traveling. When bike speeds are high , such as at downh i lls, or when motor vehicle approach speeds exceed 30 mph ,18 or where drivers often proceed through a turn at speeds higher than 10 mph, long No Stopping/No Standing Zones are necessary.19 In these conditions, people using the bikeway need relative ly long distances to slow ahead of an intersection if they have been overtaken by a turning vehicle . Shorter sight distances may be applicable where the bike design speed is moderate to low and vehicle turn i ng speeds are very low, such as at small driveways or alleys. For example, i n a protected intersection w ith a 12' bikeway setback, 25 mph traffic, and average bike speeds , the t otal clear sight distance should be at least 40', measured from the front of the last park i ng space to the po i nt where bikes becom e expose d to turning vehicles. At this distance, a person on a b i ke would have approximately 50' or 3 seconds to see a turning vehicle and react . Driver has enough time to react . Clear Sight Distance (40' shown) I l Person biking has enough time to react . (OU ) No Stopping I No Standing Zone (20'shown) Blkeway Setback (12'shown) Protected Intersections Using Bikeway Setback to Increase Visibility Protected intersections increase driver visibility of people in the crossbike and crosswalk by setting back the crossbike from the motor vehicle travel lane . The larger the bikeway setback, the easier it is for drivers to see people in the bi keway or crossb i ke without checking mirrors or turning around. In a conventional bike intersection, the bike spends a long time i n the blind spot of an approach i ng vehicle. Except at the lowest speeds, this sets up an unresolved confl ict where bike r iders must be prepared for evasive action even though they have the right of way. Conventional Intersection At a conventional intersection, the bike rider is hidden from the driver's view as the driver makes the turn . For example, in a protected intersection with the crossbike setback approximately 14'-16' from the motor vehicle lane , a car driver approaches the crossbike at an angle above 45 degrees and preferably above 60 degrees. This high angle allows the driver to easily see cyclists and keeps cyclists fully outside of the right-side blind spot on large vehicles . In contrast, in a conventional intersection, turning drivers approach the intersection at a very low angle, and would have to check mirrors and turn almost all the way around to see approaching bicycles. Protected Intersection ---------.. At a protected intersection , the bike lane is set back from the motor vehicle through/turn lane, so the bike rider is visible as the driver turns. I Protected Intersections Setting Turn Speeds through Curb Radii Research s hows that driver yield rates d ecline as speeds increase.20 As a result, motor vehicle turn speeds sho uld ge nerally be l ow er t han 10 mph in pro tected intersecti ons.2 1 This is achieve d by building corner islands with small curb radii, typically 10-15' or less, that guide d r ivers to take the turn at s lower speeds. When the bikeway setback is small or when the receiving lane of the turn is wide, a smaller curb radius is recommended . In most cases, the curb radius should not be large r t han the setback. The width of the cross -street receiving the turn also influences turn speed. This w idth should be kept as low as practica l. Pedestrian islands or centerline hardening may be used to reduce t urn speeds . Pedestrian islands can also reduce t he distance that people biking and walk i ng will be expose d to turning vehicles . 100 75 :g Q) >= 50 +-' c Q) (J .... Q) a.. 25 I 5 Driver Yielding Rates 8c Travel Speeds at Crossings 10 15 Speed (mph) 20 Lower speeds lead to higher driver yielding rates at urban roundabouts . Roundabouts share important geometric features with protected intersections. Graph source: Geruschat, D.R., Driver Behavior in Yielding to Sighted and Blind Pedestrians at Roundabouts. 2005. • 25 Protected Intersections Design, Control, & Managed Vehicles The selection of the Design, Control, and Managed vehicles informs the design of the corner radius at a protected intersection, as well as the need for any vertical features. Design Vehicle The Design Vehicle is the largest typical ve hicle that will frequently use the street. For major streets and downtown settings, a DL-23 delivery truck is a typical design vehicle . In protected intersections, it is acceptable for the design veh icle to use all of the first lane, and part of the secon d lane of the receiving street. In a neighborhood setting, a 15' car/ light truck is a typical design vehicle, allowing for a tighter turn radius . In locations where t ruck turn volumes are high, a single -unit 30'-40' truck is a typical design vehicle . A city bus should be used as a design vehicle only if a scheduled/ planned bus route makes that turn. In most cases, this affects only one corner. Turn speeds of 3-5 mph should be used for modeling the design vehicle . I Control Vehicle The Control Vehicle or accommodated vehicle is the largest vehicle that will infrequently use the street. For major streets and downtown settings, a WB -50 truck is a typical control vehicle. In protected intersection designs, this vehicle can make the turn at a very low or 'crawl' speed . It is expected to tu rn over mountable elements, and may enter the lane adjacent to its lane of origin . In a neighborhood setting, sanitation or fire emergency vehicles are control vehicles. Turn speeds should be set 1-5 mph fo r the control vehicle . For turn speeds under 5 mph, field testing or observation is recommended as software may be inaccurate at low speeds . Managed Vehicle I I The Managed Vehicle is the most common vehicle to use the street. It is typically smaller than the design vehicle which means it is capable of higher, more dangerous speeds. In most urban streets, the managed vehicle is a personal vehicle or taxi. In protected intersections, the goal for a managed vehicle is to keep turn speeds below 10 mph. In some cases, this requires that the design vehicle turns over a mountable element . I Protected Intersections Variations High -Capa city Protected Inte rsection At this t wo-way bi keway intersection, the corner island is thinner than in typical protected intersections. This shape maximizes the availab l e queuing and maneuvering space . To reduce wait times, the cross bike is also wider on the intersection approach than at the receiving side . This configuration allows more riders to wait side -by -sid e and depart at the same time. Faster riders tend to accelerate through the intersection first , and pass slower riders before reaching t he narrower receiving side. As shown in the draw ing below, the approaches are 6' wide and the receiving side 4' wide for a total 1 O' two- way approach. I •o A thin cor ner cu r b creates additional queu i ng capacity at corner. c:::======::=;----0 I fl D The departu re is widened and tapers down through the crossing to stack and release cyclists more efficiently. Protected Intersections Variations Bend-Out To set back the bikeway further, the bikeway can be 'bent-out' away from the motor vehicle lanes. This design enhances visibility by raising the angle at which cars cross the b i keway. Increasing the bikeway setback can also provide room for turning cars to wait before making the turn. As it approaches the i ntersect ion, the bikeway can be bent away from the motor vehicle lanes and toward the sidewalk . If the bikeway bends out before the intersection the taper angle should be gradual, typically 1 :4 or 1 :5, allowing for a smooth transiti on to the intersection.22 When possible, the taper should end before the crosswalk to provide good visibility for approach in g pedestrians. The bikeway can also bend ou t after cross i ng the crosswalk , and before crossing the motor vehicle lanes. Bikeway tapers on approach to gently deflect bikes (max. 1 :4 angle, 1 :5 preferred). --- Increasing the bikeway setback decreases back pressure on turning vehicles . I I I I Protected Intersections Variations Interim Materials Quick-build or in t erim materials can be used to implement protected intersection designs, even when build i ng a refuge and corner island is not possible . As shown below, a pedestrian safety area is marked between the bikeway and the motor vehicle lane. This area is outlined in a double white line to prohibit motor vehicle crossings, and a pedestrian -friendly color and texture has been applied to this area . Flexible delineators or other vertical devices are used to separate this space from the roadway. Modular speed bumps can be placed at the corner, in lieu of a concrete truck apron . A pedestrian island can be implemented w ith paint-and-posts and other quick-build materials. Vertical elements make the island easier for drivers to see, and can m a ke non -visual navigation easier. I Detectable warning surfaces alert pedestrians as t hey enter a potential conflict zone. A turn wedge with a modu lar speed bump allows large trucks to turn wh i le keeping car turns slow. Ill Accessibility for Interim Design Protected in tersections with interim materials often have flush, roadway-level pedestrian areas . These can be made accessible for pedestrians who are blind or have low vision by following either of the follow ing design and regulation option s : • Interim Island: Place detectable warning surfaces on each side of the refuge area, as would be done at a raised pedestrian island. This allows pedestrian s who are blind to use the intersection the same way other pedestrians do . The interim refuge area should include detectable elements when the pedestrian path changes direction at the refuge area , or if the refuge is so wide that pedestrians might diverge i nto the bikeway or street, or if other alignment concerns are present. • Pedestrian Safety Zone: Mark the crosswalk all the way through the surface-level pedestrian area . This does not designate the pedestrian area as a refuge or stopping place . In some conditions, this arrangement may be simpler to navigate. I Dedicated Intersections People on bikes can be given a dedicated pat h through the intersection even where there is not enough space fo r a full bike setback. By providing excellent v isib ility and low turn speeds, dedicated bikeway intersections provide key improvements over conventional bi ke lane intersections. Description To reduce conflicts between bikes and turning vehicles on busy streets, turn s peed reduction techniques and new signal phasing pattern s can complement the design of the ded i cated bike in te rsection . These techniques include corner wedges, whi ch feature a modular s peed bump or similar element ove r w hich vehicles are permitted to turn at low spee d s. Whe re t he bikeway is on a t wo -way st reet or intersects with one, the speed of left turns across t he b ikeway can be red uce d with centerline hardening or pedestrian safety is l ands. When combined wit h a protected -permissive bike signal phasing, ded icated intersections may have fewer conflicts even than s im ilarly-designed intersections with a fully protected bike signal phase due to higher signal compliance. People rid ing bikes rate these intersections as i ntermed iate i n comfort between protected intersections a nd co nv entional bi ke l a ne intersections.23 Dedicate d b i ke intersections may be more challengi ng to use than a protected intersection . With a relatively narrow buffer or no buffer, t he angle at w hich turning drivers see pedestr ians is lowe r than at protected intersections, so people on bikes cann ot always confirm that a turning driver has recog nized them and will remain stopped . In addition, people on bikes do not generally have a queue space within the intersection, a nd instead wa it before the crosswalk, or use a co nv ent ional t urn queue box to turn across traffic. I Dedicated Intersections Crosswalk Se parat or A raised element such as mountable curb or a pair of flexible delineator posts discourages turning vehicles from cutting across the bikeway w hen turning right. DD ... .< >, ~10' Bikes wait here Buffer or Cu r b A marked, painted, or raised buffer provides people on bikes with a defined travel zone at the approach to the i ntersection. I Corner Wedge & Speed Bump Speed reduction devices, such as modular speed bumps, help prevent high -speed turns and are expected to improve driver yielding. They can extend over the space used by turning vehicles but not over the bikeway or crosswalk. - ~ I A CJ Centerline Hardening Modular curbs with or without vertical delineators reduce the speed of turns across the bikeway a nd shorten the conflict zone. Crossbike / Bike Lan e Lin e Extensions II A D ---- Dedicated Intersections Implementation Guidance Vertical Elements: Vertical el ements in t he buffer a re recommended . The same vert ical sepa ration used on the rest of the bikeway can genera lly be continued until the in t ersect ion . Traversable Separation: In some cases , it is desirable t o prov ide flush or traversable buffers to allow riders to ex it the bike lane ahead of the intersect ion. If high bicycle volume or speeds are anticipated, or if t urning drivers are ex pected to block t he b i keway t emporarily, it is des i rable to provide people on bikes with points where they can exit the lane ahead of the i ntersection . The combination of fle xib i lity and separat ion from motor vehicles can be provided with a marked buffer w ith flexible del i neator posts or other d i scontinuo us , low -impact elements. To reduce i nt erference with street sweep i ng or sn ow clear i ng operatio ns , short raised elements , such as mo d ular speed bumps, should be placed in line w ith c urbs or h igher raised elemen t s, such as vertica l delineators. Curbs: Curbs or ot her hard elements that end at the crosswalk can prevent turning cars from encroachin g on the bikeway before the intersecti on . If bu ilt curbs , medians or ot her continuous vertical elements are used in t he buffer, t he recommended min i mum bikeway width is 6'. Raised Bike Lanes: Often separated by a moun t able curb but no other buffer, raised lanes can also use dedicated intersection geometry. The bike lane can s l ope down to the grade of the cross -street , or can remain slightly raised to encourage turn i ng vehicles from the ma i n street to yield . Buffer Markings: Buffers less t han 2' wide can be marked as a double white line indicating that crossing is prohibited or a wide single white line indicating that crossing is discouraged . If wider t han 2', two pairs of parallel white lines should be marked.24 Optional color pavement treatments between the white lines contribute to the conspicuity of the buffer, add aesthetic value, and reinforce the walking-friendly nature of the space. If the buffer is 4' w ide or wider, either color pavemen t or channel iz ation chevrons should be used. If the bikeway buffer is 6' or wider at the intersection, see Protected Intersections. Dedicated Intersections: Applications Dedicated intersection geometry should be considered where there is not enough space to set back the bikeway from mixed traffic at the intersection. This condition often arises when a protected bike lane runs close to mixed traffic lanes without a parking or loading lane between them. Even where a bikeway generally has a large buffer, some intersections have high enough motor vehicle turn volumes that a dedicated turn lane is preferred over a protected intersection design. The combination of high turn volumes and low turn speeds are common in high-activity, walkable downtown streets and neighborhood main streets. Dedicated intersections can be implemented at signalized, stop-controlled, and unsignalized locations, with small geometric variations. Specific design elements, such as turn wedges and centerline hardening, are also applicable to protected intersection designs. Crossbike I Bike Lane Line Extensions: Broken wh ite l ines with dashed green bars should be used across the i ntersection . Signals: Using a combinat ion of a l eading bike signal phase or i nterval, and settin g back the stop bar for mo t or vehicles , people on bikes get a head st art before cars start turning. A Lead i ng Bike+ Pedestrian Interval (LB I) can be prov ided if a shared through /turn lane is ne xt to the bikeway. If a dedicat ed right or left turn lane is next to the bikeway, protected -permiss ive bike signal phasing should be considered .25 Protected signal phases should be cons idered if turn volumes from the adjacent lane exceed 120 to 150 vph. Pro t ected signal phases should also be cons idered if conflicting left t urn volumes (on two -way streets) across the b i keway exceed 60 to 90 vph, or if these turns cross multiple traffic lanes.26 Signs: A modified "Turning Vehicles Yield to Bikes and Pedestrians" sign (R10 -15) is recommended at dedicated intersections.27 It is requ ired in jurisd ictions where pedestrians and bikes do not automatically have the right of way over turning vehicles . The sign should be mounted in accordance with existing location standards . (This modified s ign is experimental under the 2009 MUTCD.) I Dedicated Intersections Reducin g Turn Speeds and Mitigating Conflicts Lack in g a full bikeway set back, dedicated intersecti ons typically make use of tu rn speed reductio n techniques . Most of these techniques are also applicable on protected and major- minor intersections. Signal strategies and advance stop bars are also appl icable in most situations, b ut geometric s peed reduction techniques are often easier to i mp l eme nt . These techni qu es are applicable w hether or not dedicated turn lanes exist adjacent to the bikeway. Bi keway-Cro sswalk Conflicts • Gradua lly bend the bikeway (3 :1 ang le at steepest) as it approaches the crosswalk; straighten before crossing the crosswalk .28 • Raise t he pedestrian c ro ssing over the bikeway. The bike climbing ramp should be gradual (1 :12 or shallower), and a 6' flat approach area should be provided to allow bikes to stop without slipping backward.29 I Right Turns , and Left Turns from One -Way Streets • Create a tighter effective corner radius , using mountable elements if necessary to accommodate truck turns. • Install speed reduct ion de vices , suc h as mod u lar speed bumps or a mountable truck apron, inside the swept path of large vehicles or all vehicles . • Install a median island or cente r line hardening on the receiving street to prevent 'corner cutti ng.' • Raise the bikeway crossing. • Provide a leading bike interva l , protected bike phase, or protected - permissive bike phase . Left Turns from Two-Way Streets • Insta l l a median refuge island or centerline hardening on approach st reet and receiv i ng street to prevent 'corner cutt i ng .' • Ra ise the bikeway crossing. • Pro vide a leading bike in t erval, lagging left turn phase, or protected bike phase . Dedicated Intersections Variations Dedicated Turn Lane At locations with high volumes of motor vehicle turns, a right turn lane or a left turn lane (on one -way streets) is somet i mes implemented next to a protected b i ke lane. A protected or protected - permissive bike signal phase is recommended. Bend-In 'Bend -in ' approaches can be implemented where pedestr ian bulbouts already exist and cannot easily be altered. The bend -in bikeway intersection approach reduces bike speeds, increases visibility between people in the bikeway and people driving, and reduces the likelihood of visual obstructions between people driving and people on bikes. This des ign is compatible with a variety of signal designs. I Minor Street Crossings The point whe re a bikeway crosses a minor street or driveway is a transition zone between a mode rate- speed , signalized traffic environment and a very-low speed street. A well-designed minor-street in t ersection gives everyone-people driving, biking, and walking-a clear indication that bikes and pedestrians have the priority when crossing the minor street. In addition, minor intersection redesigns are an opportunity to improve pedestrian safety and access as well. Many major streets have no existing crossing accommodations for pedestrians at minor streets. Minor crossing features, such as compact corners, can also reduce pedestrian crossing distances and increase visibility, creating a safer overall bicyclist and pedestrian env i ronment . Description Minor street crossi ngs use compact corners and raised elements to keep tu rn speeds low. The raised crosswalk and bike way indicate to drivers that they are entering a low -s pee d environme nt, and m ust pre pare to yiel d to othe r users. Traffi c control devices, such as signals, are uncomm on. Ensu r i ng a clear approach sightline is essentia l t o enco urage d rivers to yield to peo ple in t he bikeway or t he cross wal k. On minor street crossings, a number of design features work to ke ep speeds low. These in cl ud e pedestrian islands or b ulbou ts, marke d ped estrian safety zo nes, planters, in - street b i ke parking, or b ike share stations. As in dedicated intersectio ns, turn wedges an d /or hardened centerline t reatme nts can re duce t urn spee d s whi l e p rov iding t urn flex i bility fo r emerge ncy vehicles a nd trucks. I Minor Street Crossings Clear Sight Distance A clear ap p roach s ightline gives drivers time to see and yield to people in t he crossbike, a nd gives people on b ike or on foot time to see and react to turning cars. Raised Crossing Raised crossings improve bicyclists' visibility and reduce the speed at which vehicles turn by bringing the veh icle crossing up to (or near) the sidewa l k level. In addition , t he raised crossing is a signal to turn i ng ca rs t hat through -moving bikes and pedestrians have the r ight of way. Compact Corners Sma ll turn rad ii force turn in g drivers to slow down. If there is no raised cros s i ng , the corner ra d ius is the pri ma ry method to reduce turn speed . (([]) Crossbike & Crosswal k ----~, Markings • Crossbike a nd crosswalk --Detectable Wa rning markings provide consp icuity to people on bike or on foot . High -visibility ma r k i ngs provide the formal crosswalk and cross b ike . I A 0 I ~ fl D Surfaces Dete cta ble warn i ng surfaces alert pe ople who are blind or have low vision that they are entering an i ntersection . Minor Street Crossings Implementation Guidance Raised Crossing slopes should be designed for very low speeds . On minor streets that accommodate through traffic, a 5-8% slope is recommended. On alleys and driveways, a slope of up to 15% may be used .30 When a sharp grade is used , care shou l d be taken to design the top of the raised crossing smoothly enough that the control vehicle can climb and descend at a low speed (<5 mph) wi tho ut bottoming out. If large vehicles such as buses routinely use the ramp, a sinusoidal shape should be used for the vehicle ramp and crossing.31 The sidewalk and bikeway may gradually slope downward to meet the raised crossing as they approach the intersection. These slopes should be 1: 24 or gentler in most cases . Even an ADA- compliant slope (1 :12), can jolt riders on a bike, in a wheelchair, or using other mobility devices . If necessary, the entire roadbed can be slanted gradually up when approaching the minor-st ree t intersection, generally at no more than a 1 :20 slope.32 Compact Corner radius should be designed based on the effective turning radius, which is typically larger than the curb radius itself since vehicles rarely turn from a position exactly at the curb . Detectable Warning Surfaces should be placed across the transition between the sidewalk and the crosswalk, and may extend across the bikeway. Green or another contrasting color may be used across the bikeway to support people with l ow vision in distinguishing between the crossbike and the crosswalk. Clear Sight Distance is determ ined by the des ired bicycle approach speed.33 Particularly where there is no raised crossing, green bike intersection markings should be used in the crossbike. Provide detectable warning surfaces across the entire raised crossing unless local guidance indicates that it should be limited to the cros swa lk entrance. I Signal Phasing Strategy Signal phasing strategies are a core tool for be tter intersection des ign. This section provides signal phasing options for protected and dedicated bike intersections, with an emphasis on mitigating conflicts between motor vehicle and bicycle movements. It supplements, and in some cases updates , the NACTO Urban Bikeway Design Guide's recommendations for bicycle signals. The following phas ing opt ions reflect the recent experience of North American cities and should be adapted to local standards and practices . Trade -offs between comfort and convenience are present in all s ignal operations. Motor vehicle turning movements consume a large amount of time and space at intersections. At the same time, many riders express a comfort preference for protected bicycle signal phases, with ful ly separate motor vehicle turn phases. However, in some cases, fully separated phases may result in longer wait ti mes for both bike and automobile travel, reducing perce ived convenience . Setting signal progress ions to bike -friendly speeds can reduce bicycle delay caused by a separate turn movement, while supporting bus transit relia b ility and disincentivizing speeding. At some intersections, it is more effective to provide flexibility to peop le walking and biking, allowing them to proceed even after motor vehicles begin to turn across the bikeway. This operation is represented by leading bike intervals and protected -permissive bike s ignals. The relative risks and efficiencies among these options are impo rtant conside rations for the practitioner. Intersection and corr idor signal timing analysis, the existing risks and issues at an intersection, and an understanding of how peop le using the street will respond to signals are all important factors in bike intersection operations dec isions. I Signal Phasing Strategy Leading Bike Interval (LBI) & Lagging Left Turn A lead i ng bike interval gives people on bikes a head start in front of turn i ng vehicles, prov iding a priority position in the r ight of way. The lead i ng pedestrian interval (LPI), which can accompany the LBJ , is a proven measure to reduce serio us crashes and injuries for pedestrians .34 Bike signal hea d s or "Bikes Use Pedestrian Signal" plaques may be used to provide LBls i n some jurisdictions . This use of a bike -symbo l signal is considered exper i menta l under MUTCD Interim Approval IA -16.22 .35 On two -way st reets with signali zed l eft turns , bike and through/right motor vehicles shou l d generally be given the first phase, with right turns yielding to bikes and pedestrians. Left turns are then accommodated in a dedicated phase after oncoming bikes receive a red signal, to reduce bi ke -left turn conflicts and pedestrian -left t urn conflicts. Phase A I --~~ I I ~ 111 ·--+ Phase B .. ~ • - 111 -·--+ TURN ING _. ~EHIC LES I • V tot PhaseC • . . • • • • • •• • • • • • •• •• •• - '--- 111 ······~ ····--+ Signal Phasing Strategy Bike Scramble The bicycle all-cross phasing is an option at high bike -volume locations to allow more time t o move t hrough the intersection, especially if diagonal movements are in high demand. The bike scramble is compatible with protected intersections, s i nce the geometric scheme organizes otherwise conflict i ng right-angle bike movements. It is also useful at other intersections where an LB J might otherwise be used to mitigate motor vehicle turn conflicts, but where bike turn volumes are also high . Pedestrian signals should be placed on the pedestrian island or corner is land where practical to avoid signalizing the bike -pedestrian and bike -bike interaction . D ••• ~ --II *.__· ___ ____..,._.,.* . - . . . {t ~ &f0 USE PED SIGNAL I IIJ ID I Signal Phasing Strategy Protected-Permissive Bike Signal The protected -permissive bike signal, also known as the Split LBI, allows through -moving motor veh icles to start at the same time as parallel bikes. Bike and pedestrian movements continue, as turning motor vehicles receive a flashing yellow arrow turn phase . Protected -permissive signal phasing can reduce the number of conflicts per turning motor vehicle, even compared with full signal protection .36 Protected -permissive bicycle signal operations allow riders to decide for themselves whether it is safe to go during the motor vehicle phase , or whether to wa it for a fresh protected bike phase. Protected -permissive bicycle signals are most applicable on streets where turn volumes are moderate to high and vehicle storage is nee ded, but prevailing motor vehicle speeds are relati vely low, preferably 25 mph or below. This use of a bi ke -symbol signal is considered experimental under MUTCD In terim Approval IA -16 . Phase A Phase B I I .. :. • .. ··-+ .. ··-+ I Signal Phasing Strategy Protected Bike Signal Fully separate signal phases for bikes and turning veh icles provide a green b i ke phase and pedestrian Walk phase during a motor vehicle red arrow phase, followed by a motor vehicle turn phase accompanied by a red bi ke signal.37 This condition is most applicable at high -volume turn locations (above 150 turns per hour), or where prevailing speeds are 30 mph or higher, where motor vehicle yielding is low, or at locations where multiple lanes turn across a bikeway.38 Phase A Phase B l __ I l_IJlJ . .... . ! .. ';.,.~ •• ··....+ I Build Toolkit Implementation of safer crossings can wield a full suite of design tools, from tactical to interim to capital construction . A wide variety of modular, pre -cast, and cast-in -place materials can be used to separate bikeway approaches from motor vehicles. The following suites of materials have been used successfully i n North Amer ica. Markings & Color Directional marki ngs, especially using green color, highlight the "cross -bike" path through the intersection and draw attention to potential conflict zones . Markings are also used to create two-stage turn boxes or bike boxes as storage for bikes waiting to cross, increasing intersection efficiency and comfort. I -~ ~ Quick-build 0 Paint & Posts Bollards and other low -vertical elements can be installed to formalize exclusive turning and re f uge spaces . They can be implemented relatively quickly and at low cost. Low Dellneators Low -to-the-ground objects such as temporary curbs are useful where a long mountable curb is desired but impractical. Angling the elements toward the center of the roadway allows bikes to easily exit the b ikeway while dissuad i ng drivers from entering the bikeway. 0 0 Mountable Rubber Speed Humps Molded rubber and plastic speed humps are mountable by motor vehicles at low speeds suitable for turns. They are an easy -to -implement speed reduction alternative to raised truck aprons or textured pavement. These off-the-shelf devices can be secured to asphalt or concrete road surfaces. Example Combination: Paint and posts Channelization markings and flex posts for buffer Modular speed hump for large-vehicle overrun area and /or inside the channelization area to prevent early turns Optional: flow-through planters Bike Parking Bike parking, street-grade bike corrals, and bike share stations make positive use of the clear zone . Si nee these features do not block the view of approaching cars and bikes , they can replace automobile parking at the approach . Modular Islands & Bulbs Modular refuge islands and bus boarding islands can be used at bikeway i ntersections , creating a level accessible boarding platform or simply a protected waiting area between the bikeway and the street. Surface Concrete Concrete elements can be implemented for relatively low cost where drainage is not an issue . Concrete refuge islands, extruded curb , and cast-in -place curbing, can often be built by sidewalk or highway repair crews. Pre -cast concrete, including parking stops or specially designed mountable elements, is more expensive but, like other modular elements, can be i mplemented quickly. Permanent Full Construction In larger capital implementations or roadway reconstruction, raised bike lanes and full truck aprons can be built to create a long-lasting addition to the streetscape. I Citations I 1. People for Bikes (2019). Inventory of Pro- tected Bi ke Lanes. Retrieved from https"// peopleforbikes org/green -lane-proiect/ inventory-protected -bike -lanes/ 2. NACTO analysis of NHTSA FARS data : Non-Freeway Urban Bike Fatalities (U.S., 2017): Intersection or Intersection -Related: 226 Total Known: 531 Percent Intersection or lntersection -Relat - ed: 43% 3. Fitzpatrick, K. and Schneider W. (2005) Turn speeds and crashed within right-turn lanes (Report No . 0-4365-4). College Station, TX : The Texas A&M University System 4. New York City Department ofTransporta- tion (2016, August). Don't Cut Corners: Left Turn Pedestrian and Bicycle Crash Study. Retrieved from: http"//www.nyc .gov/html/ dot/downloads/pdf/left-turn -pedestrian - and -bicycle -crash -study pd f 5. New York City Department of Transporta - tion (2018 , September). Cycling at a Cross- roads: The Design Future of New York City Intersections. https"//www1 nyc gov/html/ dot/downloads/pdf/cydiog-at-a-cross - roads -2018 pdf 6. Monsere , C., McNeil, N., Sanders , R., Wang , Y, Burch f ield , R. Schultheiss, W. (2019). Contextual Guidance at Intersections for Protected Bicycle Lanes. (Report No. NITC- PF-987). National Institute for Transporta - tion and Communities (NITC) 7. Madsen , T.K.O., Lahrmann, H, (2017). Comparison of five bicycle facility designs in signalized intersections using traffic conflict studies. Transportation Research Part F: Traffic Psychology and Behaviour. 46(B), pp . 438 -450 . 8. San Francisco Municipal Transportation Agency (2017). 9th Street/Division Street Protected Intersection Proof-of-Con - cept Evaluation . Retrieved from:https"// www sfmta com/sjtes/default/files/re- ports -and -documents/2018/03/9th divi- sion fact sheet pdf 9. New York City Department ofTransporta - tion (2018, September). Cycling at a Cross - roads: The Design Future of New York City Intersections. https"//www1 nyc gov/html/ dot/down loads/pdf/cycli ng -at-a-cross - road s-2018 pdf 10. Aldred, Rachel et al (2016). Cycling pro- vision separated from motor traffic: a systematic review exploring whether stated preferences vary by gender and age. Trans- port Reviews. 37(1 ), pp . 29 -55 . 11. Seattle Department ofTransportation (2017). Seattle Streets Illustrated. 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Department ofTransportation Federal Highway Administration (2009). Manual on Uniform Traffic Control Devices . Re - trieved from : https"//mutcd fhwa dot gov/ pdfs/2009/pdf index htm 25. New York City Department ofTransporta - t ion (2018, September). Cycling at a Cross - roads: The Design Future of New York City Intersections. https://www1 .nyc gov/html/ dot/downloads/pdf/cycliog-at-a-cross - roads -2018 .pdf 26 . Massachusetts Department of Trans- portation (2015). Separated Bike Lane Planning and Design Guide. Retrieved from: https·//www mass gov/lists/separat- ed -bi ke -lane -planning-design -guide 27. U.S. Department ofTransportation Federal Highway Adm i nistration (2015, May). Sepa - rated Bike Lane Planning And Design Guide. Retrieved from : https://www.fhwa dot gov/ environment/bicycle pedestrian/publica - tions/separated bikelane pdg/separated - bi kelane pdg pdf 28. Massachusetts Department ofTrans- portation (2015). Separated Bike Lane Planning and Design Guide . 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Retrieved from: https"//www mass gov/lists/separat- ed -bike -lane-planning-design -guide 34. Van Houten , R., Retting , R., Farmer, C., Houten , J., Field Evaluation of a Leading Pe - destrian Interva l Signal Phase at Three Ur- ban Intersections. Transportation Research Record : Journal of the Transportation Research Board 1734, 86 -92, Washington DC: Transportation Research Board 35 . US Department ofTransportation Federal Highway Administration (2013). Manual on Uniform Traffic Control Devices : Interim Ap - proval for Optional Use of a Bicycle Signal Face (IA -16). Report No. HOT0 -1. Retrieved from: https ://mutcd ,fhwa .dot.gov/resourc - es/interim approval/ia16/ 36 . New York City Department of Transporta- tion (2018 , September). Cycling at a Cross - roads : The Design Future of New York City Intersections. https"//www1 nyc gov/html/ dot/down load s/pdf /cycling-at-a -cross - roads -20 18. pdf 37. Furth, P., Koonce P., Miao, Y., Peng. F., Litt- man, M. (2014). Mitigating Right -Turn Con - flict with Protected Yet Concurrent Phasing for Cycle Track and Pedestrian Crossings. Transportation Research Record 2438(1 ). pp . 81 -88 . 38. Massachusetts Department ofTrans - portation (2015). Separated Bike Lane Planning and Design Guide. Retrieved from: https"//www mass gov/lists/separat- ed -bike -lane -planning-design -gu ide Additional Resources Monsere, C., Dill, J ., Clifton , K., McNeil , N., (2014) Lessons from the Green Lanes : Evaluating Protected Bike Lanes in the U.S. Portland , OR : Transportation Research and Education Research Center Harkey, D., Carter, D., Barlow,J ., Bentzen , B., (2007) Accessible Pedestrian Signals : A Guide to Best Practices . National Coopera - tive Highway Research Program Web -Only Document 150 , Washington DC : National Cooperative Highway Research Program Blackburn, L., Zegeer, C., Brookshire, K., (2017) Guide for Improving Pedestrian Safety at Uncontrolled Crossing Locations (Report No. FHWA -SA -17 -072) Washington DC: Federal Highway Administration Office of Safety I